Furnace grate



' Patented Sept. 9, 1941 UNITED STATES PATENT OFFICE I I 2,255,373 I FURNACE Guara- Alfred E. Blake, CaldwelLN. .1. Application February 14, 1940, Serial No. 318,794

2 Claims.

scriptionin connection with the accompanying drawings, in which:

Fig. 1' is a vertical taken along the line embodiment of the invention;

Fig. 2 is a. plan view; 'Fig. 3 is a section along section partly broken away the line 3-3 of Fig. 4,

showing a modification; and

and at the same time access of air to the combustion zone is facilitated.

In carrying out this invention, spaced metallic horizontally-disposed s pporting surfaces for ashes and fuel are provided at one level and other similar surfaces are provided at a lower level and staggered with respect to the first ones so that ashes passing through the spaces between the upper supporting surfaces are stopped by the lower supporting surfaces. Provision is also made by means of which ashes can be removed whenever desired and in a controlled manner from the supporting surfaces through the spacesbetween them, thus making it possible to provide any desired depth of ashes beneath the combustion zone in accordance with the nature of the combustion material or character of combustionit may be undergoing.

One of the very important features of this invention is in having the supporting surfaces for the ashes so constructed and arranged that, while the ashes can be readily and easily removed therefrom, accidental escape of ashes and waste of fuel mixed therewith is avoided; The lower supporting surfaces for the ashes are of such dimensions and are so located with respect to the spaces between the upper supporting surfaces that a continuous stream of ashes cannot flow through the upper and lower openings or spaces which are offset horizontally with respect to each spaces pile up on the lower supporting surfaces until the piles reach thoupper surfaces, there is no danger of the fuel bed drifting down too far automatically. This safety factor is due to the fact that the lower supporting surfaces are' wide enough to prevent the ashes from automatically pouring of! of them because of the angle of reprise.

of the ashes even when the depth of ashes on the lower supporting surfaces exceeds the distance between the lower and upper supporting surfaces and cause ashes to pile up above the space between the upper supporting surfaces.

The invention will be understood from the denular. space I9 is left' betweeg other. Even if ashes passing through the upper Fig. 4 is a plan view of the modification.

Reference character I indicates a furnace that is circular in crosssection and is provided-with a water jacket 2. A'n'ash guard 3 is shown along the inside of the bottom edge of the furnace The walll of the ash pit below the furnace is circular in cross section, and the furnace iis supported on this wall. An annular plate or ashsupport 5 has its outer edge resting on the wall 4. The offset portion 6 is also annular in shape and is provided with a circular opening I at its middle. The outer edge of the portion 6 is connected to the inner edge of the plate 5 by a vertical cylindrical wall 8. 1

I A revoluble toothed spider 9 having teeth Ill l along its outer periphery is driven by a spur which may receive its power from any gear H convenient source. Arms I2 of the spider 9 connect its outer rim to a central portion I3. A stationary support H has a bearing plate I5 upon which the central portion ll of the spider bears.

"The reduced portion ii of thesupport i4 serves as a shaft for the spider 9, this shaft i6 passing through a hole in the ce ter of a circular plate l5 and a hole in the center of portion l3 of the spider 9, and terminates in a headed A wear plate I8 is provided between the plate l5 and a shoulder'on the support [4. An anthe outer edge of the plate l5 and the innere e of an annular plate 20 that is concentric Iw%h" the plate 5 and is on a level with it. An .an ar plate 21 is offset from the plate 20 on the s amelevel with the offset portion 6, and is smaller than the opening I. A vertical cylindrical wall .22 connects the outer edge of the offset portion 2| to 'the inner edge of the annular plate 26. A central. opening 23 is provided in the portion 2! around the shaft H for' ashes. Supports 24 are also provided for the portions 6 and 2|.

Rakes or ploughs 2! are attached to the arms I! of the spider '0, and extend downwardly through the space 2! between the outer edge of the plate 20 and the wall I. These ploughs or rakes are so shaped and located that when they are moved in a circumferential path they push ashes from the surface of the portion 8 and the i-l of Fig. 2, showing an portion I1. Q

. corner formed by the wall 6 and portion 6, ca

4 with the plate 42.

ing the same to fall through the opening I. Bakes or ploughs 30 similar to the rakes 2Lare connected to the lower side of the arms I! of the spider 9 in position to remove ashes in like manner from they surface -.of the portion 2| through the opening 23.

A recess 3| is shown in the outer surface of the wall 4 to accommodate the shaft of the pinion II. An opening 32 is provided at the upper portion of the wall 4 to accommodate an edge of the gear so that it can mesh ,with

' the gear l0. An annular recess 33 is provided the wall 4 on a level with thetop of the ,sup-

port 40,'and an annular plate 42 is supported on the support 40 and ledge 4|. The offset portion 43 of the plate 42 is provided with a central circular opening 44, and the outer edge of this plate 43 is connected to the inner edge of the plate 42 by a vertical cylindrical wall 45.

A support 46 rests upon the bottom of the ash pit. This support is provided .with arms '41 which carry an annular support 48 for the lower race -49 of a ball bearing 56. The upper race 5| of this ball bearing is provided with a circular are so'shaped that ashes are pushed off of the surface 42 and the outer portion of the surface 64 through the space 65.

Ploughs or rakes are carried by inwardly extending horizontally disposed members 14, that are attached to the revoluble plate 64. The

- ploughs 13 extend through the opening 68 and rack '52, which meshes with a gear 53 mounted upon a shaft 54 .that revolves in a' bearing 55 on the support 48 and a bearing 56 in the wall 4. This shaft carries a gear 51 that may be driven in any convenient way.

A revoluble circular plate 60 is attached. to and carried by the upper race II of the ball bearing on a level with the plate 43. It has a central opening 6| with a cylindricalshield 62 extending downwardly from the edge of this opening. A vertical cylindrical wall 63 connects the outer edge of the plate 60 with the inner edge of an annular plate 64 which is on a level The plate 64 is of such a sizethat an annular space 65 for passage of ashes is left between the outer edge of the'plate 64 and the inner edge of the plate 42.

An extension 66 of the support 46 carries a circular plate 61 at its upper end on a level with the plates 42 and 64. Theplate 61 is of such a sizev that an annular space 68 for ashes is left remove ashes from '.the surface of the plate through the opening 6|. The front edges 15 and I6 of .the members "are so shaped as to remove ashes from the inner portion of the plate 64 and from the whole upper'surface of the plate 61, respectively.

In both embodiments of the invention, the lower ash-supporting surfaces are so located with respect to the ash openings thereabove that the passage of ashes through these upper openings ohto these lower plates or supports is stopped because of the angle of repose of the ashes before the ashes pass through the second or lower set of openings. The depth of ashes in thefurnace or on the grate is easily regulated by controlling the speed at which the rakes or ploughs remove the ashes from the surfaces of the grate.

Upwardly extending knobs or projections may be provided upon any of the moving surfaces upon which the ashes rest, so that as they are moved they help to break up or wear away by attrition any clinker or hard obstructions so that the pieces can readily pass through the spaces provided for the ashes.

The operation of' the grates will be obvious from the above description as it will be seen .that as soon as enough ashes pass through the upper series of openings, such as the spaces l9 and 29 in Fig. l, to prevent more ashes from reaching the lower set of surfaces, such as the surfaces of plates 6 and 2| in Fig. 1, the flow of ashes will stop due-to the angle of repose of the ashes on the lower surfaces. When the depth of ashes on the upper surfaces, such as the plates 5 'and 20in Fig. l, is suflicient to cause the zone of combustion in the furnace to be at 5 jacent saidwalls over the edges of the lower between its outer edge and the inner edge of the plate 64.

Ploughs orv rakes 69 are carried by outwardly extending horizontally disposed members 10 at- 60 tached to the revoluble plate 64. These rakes 69 extend through the space and are so shaped and locatedas to. remove ashes from the portion or plate 43 through the. opening 44.

The front edges II and 12 of'the members 13 surfaces that are remote from said walls, the upper supporting surfaces being staggered with respect to lower ones and so disposed with respect thereto that the angle of repose of ashes keeps the ashes from automatically flowing off of the grate.

2. A grate in accordance with claim 1,-in

which --the scrapers move in circular paths.

ALFRED E. BLAKE. 

